This application Chicagoland TrialNet Clinical Center is in response to the RFA -DK-13-010 Type 1 Diabetes TrialNet Clinical Centers (U01). Here we describe a joint effort from the University of Chicago and Advocate Children's Hospital (ACH) sites (Park Ridge and Oak Lawn, Illinois) and Advocate Health Care (AHC) to create a new Clinical Center in the Chicagoland area. These organizations along with our other affiliate (Lurie Children's Hospital) and partner sites saw over 9000 patients with type 1 diabetes (T1D) in 2012. Together, these practice sites along with other participating key adult and pediatric diabetes practitioners from Chicago reach over 12 million individuals within a two-hour drive of a screening location. The Chicago community, strong supporters of the Juvenile Diabetes Research Foundation (JDRF) and American Diabetes Association (ADA), has been under-represented in clinical trials for Type 1 Diabetes (T1D). This partnership will bring together the resources of major medical centers committed to T1D research and clinical care to reach more of the estimated 100,000 individuals with T1D in the Chicagoland area (about 0.8% of the area population) and their families, as well as the 2000 projected new cases of T1D and their families each year. This outreach will involve diverse communities from some of the wealthiest to some of the most underserved in the United States. We will build on our success in creating the largest database for monogenic diabetes in the United States. We will engage the greater Chicagoland community through innovative social media and direct communications combining media support, direct visits to local practices, community events supported by our institutions and partners and outreach to large networks of faith communities. The University of Chicago has been committed to diabetes research for over 100 years, and together with Advocate Children's Hospital and other partners we will bring a new sense of energy, organization, and purpose to TrialNet recruitment and screening in the Chicagoland region.